Conventional printing methods include at least two categories. The first category is a digital printing method which includes a print-on-demand method and a publish-on-demand method. The print-on-demand method has been used to print two-sided copies of mass mailing advertisements with some individualized information printed on each of the copies. However, the print-on-demand is only suited for small scale production, too small for use on large scale commercial applications, because, among other reasons, the print-on-demand method is limited to printing one distinct final print-product per page.
The first category also includes the publish-on-demand method, which has been used for printing books and magazines where the copies are produced in a low volume, around one hundred copies. In this method, identical copies, without personalized data, can be published, which is ideal for individuals who want to print a small quantity of family histories or other memoirs. Because the copies printed using the publish-on-demand method are all identical, however, no individualized copies can be printed.
The second category is used in the printing of books, magazines or newspapers where thousands of identical copies are printed using an off-set printing method. This category is referred as commercial printing. In commercial printing, rather than printing individual final print-products, a signature page is printed. FIG. 1 illustrates an example of a signature page 21 which is an amalgamation of final print products including date pages. Hence, when the signature page 21 is folded and cut, it becomes many date pages. The signature pages are ideal for the commercial printing method because the signature pages are readily adaptable to a high-volume, high-speed printing and binding production assembly line. In particular, each signature page includes print-marks such as cutting marks 25, and folding marks 26. When a large number of the signature pages are printed, the print-marks are utilized in a subsequent assembly line production of final print-products, which in this example are calendars. In the assembly line processing, the signatures are folded at the trimming mark.
However, the commercial printing method cannot print individualized final products since the commercial printing process does not provide for variation of the printed matter.
The printing process is typically assisted by computer print applications such as Adobe Illustrator.RTM. and Quark.RTM.. In the conventional print applications, the textural and graphical contents of print-products to be produced are entered using the print applications. Once the contents are entered into the print applications, the applications generate print description language (PDL) commands with which to drive printers to print the entered contents.
Recently, Postscript.RTM. has become the most popular page description language for printers. As a result, once a print application generates the contents in Postscript.RTM. commands, most printers can receive and interpret the Postscript.RTM. commands to print the content.
In order to print a page with a number of final products as in the signature page, an imposition file must be generated. The imposition file includes the PDL commands describes how each final print product is to be arranged within the signature page. For example, in FIG. 1, the imposition file describes the location of the date pages for "January 6" 23 and "January 8" 27. In addition, in imposition files generated by the conventional print applications, every aspect relating to the signature page must be hard coded. For example, the imposition file must include commands relating to fonts of the texts, location of each line, location of each text for each date page, among others. A large computer memory space is thus required to maintain the imposition files. Furthermore, any alteration to the imposition files requires a cumbersome revision process because an entire new imposition file must be generated even if only a small part of the signature page is to be changed.
These deficiencies are amplified when individualized copies are to be printed on the voluminous production scale of the commercial printing method. For instance, for each copy or distinct print product to be printed, a new imposition file must be created to include the different information in each print product. This would require extremely costly expenditures in computer capital investments and an extremely high level of computing time.